Francesca Iannacone1, Francesco Di Capua2, Francesco Granata3, Rudy Gargano3, Giovanni Esposito4. 1. Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, via Gaetano di Biasio 43, 03043 Cassino, Italy. Electronic address: francesca.iannacone@unicas.it. 2. Department of Civil, Architectural and Environmental Engineering, University of Naples Federico II, via Claudio 21, 80125 Naples, Italy; Department of Civil, Environmental, Land, Building Engineering and Chemistry, Polytechnic University of Bari, Via E. Orabona 4, 70125 Bari, Italy. 3. Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, via Gaetano di Biasio 43, 03043 Cassino, Italy. 4. Department of Civil, Architectural and Environmental Engineering, University of Naples Federico II, via Claudio 21, 80125 Naples, Italy.
Abstract
This study investigated the feasibility of coupling simultaneous partial nitrification and denitrification (SPND) to biological phosphorus removal in continuous-flow intermittently-aerated moving bed biofilm reactors (MBBRs) fed with different carbon sources, i.e. ethanol and acetate. Bacterial cultivation at pH 8.2 (±0.2), 26-28 °C and SRT of 4 day and microaerobic/aerobic MBBR operation allowed to achieve average dissolved organic carbon (DOC), total inorganic nitrogen (TIN) and P-PO43- removal efficiencies (REs) of 100%, 81-88% and 83-86% at HRT of 1 day, dissolved oxygen (DO) range of 0.2-3 mg L-1 and feed C/N and C/P ratios of 3.6 and 11, respectively. Acetate supplementation favored a diversified microbial community, while overgrowth of heterotrophs was observed when increasing feed C/N ratio in ethanol-fed MBBR. Illumina sequencing displayed the presence of putative phosphorus accumulating organisms (PAOs) such as Hydrogenophaga and Pseudomonas in MBBR biofilm and suspended biomass, whereas no typical NOB was identified during the study.
This study investigated the feasibility of coupling simultaneous partial nitrification and denitrification (SPND) to biological phosphorus removal in conpan class="Chemical">tinuous-flow intermittently-aerated moving bed biofilm reactors (MBBRs) fed with different carbon sources, i.e. ethanol and acetate. Bacterial cultivation at pH 8.2 (±0.2), 26-28 °C and SRT of 4 day and microaerobic/aerobic MBBR operation allowed to achieve average dissolved organic carbon (DOC), total inorganicnitrogen (TIN) and P-PO43- removal efficiencies (REs) of 100%, 81-88% and 83-86% at HRT of 1 day, dissolved oxygen (DO) range of 0.2-3 mg L-1 and feed C/N and C/P ratios of 3.6 and 11, respectively. Acetate supplementation favored a diversified microbial community, while overgrowth of heterotrophs was observed when increasing feed C/N ratio in ethanol-fed MBBR. Illumina sequencing displayed the presence of putative phosphorus accumulating organisms (PAOs) such as Hydrogenophaga and Pseudomonas in MBBR biofilm and suspended biomass, whereas no typical NOB was identified during the study.